Air Curtains  are often referred to as an air door, air barrier, or air screen, is a device that uses fans to create an invisible air barrier over the doorway, dividing two distinct environments while allowing free access for people and vehicles.

The energy-efficient air screen increases occupant comfort while reducing heating and cooling expenses by up to 80%. It also protects the interior environment.

It keeps the atmosphere free of draughts, dust, airborne pollutants, odours, and flying insects and vermin. It also blocks the entry of hot or cold air.

The air doors use electricity while they are in use, but they can result in net energy savings by minimizing the heat transfer between two spaces (through mass transfer while the air doors are closed).